The invention relates to bars screens, and more particularly to bar screens having cleaning rakes.
Bar screens are used to collect debris from channeled water flowing into water treatment plants, industrial sites, drainage facilities, or overflow control facilities. A bar screen generally includes a bar rack and a cleaning rake. The bar rack includes a series of aligned metal bars that are at least partially positioned within the channeled water. The cleaning rake is movably coupled to the bar rack and lifted along the length of the bar rack to periodically engage the bar rack and remove debris that has accumulated on the upstream side of the bar rack. The cleaning rake includes a plurality of teeth that are cantilever mounted along the length of the cleaning rake.
The teeth are typically made from steel or cast-iron for strength. The general shape of the teeth is dictated by the size of the openings between adjacent bars of the bar rack, the degree that the teeth are required to penetrate into the bar rack, and the engagement clearances necessary to avoid metal to metal contact. In light of these requirements, the teeth are typically relatively long and thin. These prior art teeth can be easily bent if they are improperly aligned with the bar rack or if they engage debris that is trapped between the bars. Once a single tooth is bent, the entire cleaning rake cannot properly engage the bar rack, rendering the bar screen inoperable. Therefore, the bent teeth of the cleaning rake must be replaced immediately. In addition, the channeled water must be drained to locate the problem area that caused the damage to occur, and all of the trapped debris that has collected between the bars of the bar rack must be manually removed.
The bar screen of the present invention decreases manufacturing costs by providing a tooth segment that can be injection molded. Injection molding achieves critical tolerances, insures repeatability of the parts, and offers a wide range of material options. The non-metallic tooth segment also increases the effectiveness of the bar screen by providing individual teeth that are designed to fracture such that the cleaning rake is allowed to continue functioning after a tooth or tooth segment has failed. The present invention also decreases maintenance and repair costs. Specifically, the cleaning rake continues to operate after a tooth fails allowing the cleaning rake to be repaired at a convenient time after the failure. Additionally, the tooth segments can be replaced individually or alternatively modules of the teeth can be replaced at significantly lower cost than when utilizing machined stainless teeth or cast-iron segments.
The present invention is directed to a bar screen for removing debris from channeled water. The bar screen includes a bar rack and a cleaning rake. The bar rack includes a plurality of aligned bars and is adapted to be at least partially positioned within the channeled water. The cleaning rake is movably coupled to the bar rack and includes a plurality of tooth segments or modules. Each tooth segment includes a base portion and a plurality of teeth. The base portion is coupled to the cleaning rake, and the plurality of teeth are connected to the base portion. Each tooth of the plurality of teeth is adapted to be inserted between adjacent bars on the bar rack to remove debris that has accumulated on the upstream side of the bar rack. The teeth are breakable from the base when the teeth engage immovable debris trapped within the bar rack.
The present invention is also directed to a tooth segment for a cleaning rake used in a bar screen. The bar screen includes a bar rack having a plurality of bars. The tooth segment includes a base portion and a plurality of teeth. The base portion is adapted to be coupled to the cleaning rake, and the plurality of teeth are connected to the base portion. Each of the plurality of teeth is adapted to be inserted between adjacent bars on the bar rack and configured to break from the base when subjected to a sufficient force.